Repair on brake caliper bleed thread Page 1 / 2

smac, May 8, 2:11am
I've got a stripped out thread on the bleed nipple of a cast iron calliper. Anyone ever had one of these fixed!

a.woodrow, May 8, 2:23am
You'll need to rethread to a larger diameter and fit a larger bleed nipple

kazbanz, May 8, 2:30am
Yep ---rethread to a bigger size. Helicoil/recoil wont be up to the bleeding process

steve312, May 8, 2:32am
Brake specialists can supply a complete nipple and seat (BNT have them).They come in either 1/8 gas of 1/2" UNC external thread from memory.You just need to drill the old nipple out and rethread the hole to suit one of the seats and wind it with a liberal coating of Loctite to seal it.I have replaced dozens of them, mainly on the old Trojan trailer calipers.Let me know if you have any trouble getting a replacement.I am sure I have a couple lying around the workshop I can forward to you.

smac, May 8, 2:49am
Sounds promising.but just spoke to local BNT and it was all news to him. I'll go in and eyeball them.

Existing hole is about 3/8". Thread doesn't matter 'cause there isn't one!

steve312, May 8, 3:10am
Have checked and have some 1/8" BSPT ones here if you get stuck.

realtrader1, May 8, 3:55am
Just something else to think about: consider whether the design of the calliper has allowed all the rusty junk to fall into the fluid and into the calliper.You may need to do more than just repair / replace the thread as any foreign matter in those delicate workings will be detrimental.

smac, May 8, 3:55am
Local brake guy has given me a 10X1 nipple that should be ok as the seat is still OK. Thought I had a tap but mine is 10X1.5 so will have to wait until tomorrow.

smac, May 8, 3:56am
I'm already putting in new piston and seal kit, no problem there.

steve312, May 8, 3:58am
Can be a bit tricky getting the thread exactly lined up with the seat.
Good luck.Offer still stands if you get stuck.Always nice to have an alternate option.:o)

smac, May 8, 4:20am
Thanks for the offer, but not sure how the 1/8" BSPT would help! I have a 3/8" munted hole at the moment. Need to go bigger.and preferably not tapered.

esprit, May 8, 4:32am
I used a new insert (complete with seat) in my Lotus AP Racing callipers as the alloy tends to strip out if you bleed frequently. sorted the problem nicely :)

smac, May 8, 4:42am
Well that was what I thought I'd be after, a new seat that then takes a new small nipple, but neither BNT nor the brake dude seemed to know what I was on about. Hate that.

rsr72, May 8, 4:51am
Not many crusty old knowledgeable buggers left nowadays.

steve312, May 8, 5:09am
Can get a 1/2"UNC seat and nipple for you if you get stuck.

esprit, May 8, 5:24am
Don't know about where you are, but "Just Brakes" in Penrose were the blokes that did mine, top job :)

lookoutas, May 8, 5:42am
I heli-coiled my stripped XF alloy calipers, and used the original nipples.
Never had any problems.

smac, May 9, 1:06am
Looks like the 10X1 nipple has worked. Have cut the thread.I believe straight, and there's enough meat there to hold it solid. Won't know if I was straight enough until I get pressure in the system, but if I was a little off somebody has passed on a tip: file off the point of the nipple and put a small ball bearing in there! I am the king of bodge.

steve312, May 9, 1:08am
A ball bearing under a flat based bleeder screw used to be quite a common system on some of the older car.Sometimes took a big shove on the pedal to get the ball bearing to unseat so you could bleed it.

smac, May 17, 9:21pm
steve312, if you're still about, can I get a pic (or just a link to one) of what you have! Thanks.

(the 1/2" UNC thing)

bellky, May 17, 9:43pm
Bodge job not work then!

smac, May 17, 10:45pm
Yeah the ball bearing seals, but fluid seeps out the thread when you bleed (to be expected). SO it's good enough, but not ideal.

steve is that a taper thread! When you say 1/8, is that the nipple thread size, or the seat thread size!

steve312, May 18, 12:15am
Yes, the external seat thread is 1/8 gas and is tapered. The internal nipple thread is around 1/4 UNC.I always assemble this system with a Loctite bearing retainer so once it is in, it is sealed and there to stay unless you apply plenty of heat to it.Gas thread measures 10mm in diameter, the external bleed nipple thread measures fractionally over 6mm.

smac, May 18, 12:58am
Nah that's not gonna be big enough I don't think. I have a 10mm straight thread in there now, so need to go bigger than that to get a seal. Would prefer straight too, cause then I know what I'm doing.

guest, Sep 25, 2:58pm
The Four-Wheel Anti-lock Brake System (ABS) is an electronically opaetred, all wheel brake control system. Major components include the power brake booster, master cylinder, the wheel speed sensors, and the Hydraulic Control Unit (HCU) which contains the control module, a relay, and the pressure control valves. When anyone of these malfunction the ABS Light will come on. Reference:

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